1. Field of the Invention
The present invention relates to a film removing method and a film removing agent used for the method, and more specifically to a method of removing a film and a film removing agent for removing a film from a semiconductor substrate (wafer) in semiconductor manufacturing process or from a glass substrate in liquid crystal manufacturing process.
2. Description of the Prior Art
Conventionally, dry and wet methods have been so far combined, in general, in order to remove a film such as an organic film adhering onto a semiconductor substrate (wafer) during the semiconductor manufacturing process.
In more detail, a high-frequency power is applied to the wafers arranged within an oxygen atmosphere to generate a glow discharge. That is, when the wafers are exposed to the generated glow discharge, an organic film adhering onto each surface of tile wafers can be first removed in the dry method. After that, as shown in FIG. 5(a), the wafers are dipped in a chemical to finally remove the organic film from each wafer surface in the wet method. In this wet method, in more detail, when the wafers 2 already exposed to the glow discharge are dipped in a mixed liquid 1 of concentrated sulfuric acid and hydrogen peroxide both put in a vessel, the organic film can be decomposed to CO.sub.2, CO or H.sub.2 O, so that the inorganic film can be removed chemically from the wafer, respectively. Further, as shown in FIG. 5(b), the wafers 2 are dipped in a pure water 3 put in another vessel to wash the wafers 2 on the basis of dehydrate decomposition reaction or hydrolysis reaction in the pure water 3.
As described above, in the prior art method, whenever the organic film adhering onto the wafer is removed, the dry and wet methods are combined with each other. In the dry method, oxygen plasma is generated within the oxygen atmosphere by the reaction activity due to the glow discharge by the high-frequency power, so that the temperature of the chamber increases as high as 300.degree. to 400.degree. C. As a result, there arise various problems in that the aluminum wiring portions formed on the wafer project abnormally or in that the organic film itself is hardened so that the organic film cannot be peeled off from the wafer.
In addition, in the wet method, since a large amount of the mixed liquid of concentrated sulfuric acid and hydrogen peroxide is used, there exists another problem in that the processing of the waste liquid is costly.
Further, since the dry and wet methods are combined with each other, work time as long as about four hours has been so far required to remove the organic film from the wafer, thus causing another problem in that the productivity is low.